Asphalt coated shell



Fatentecl Sept. 12, 1933 ASPHALT COATED SHELL William R. Parker and Willie L; Holbrook,

Houston, Tex.

No Drawing. Application June 14, 1932 Serial No. 617,253

1 Claim. (Cl. 106-31) 7 This invention relates to a process or method for making an asphalt coated shell adapted for use in road building, road surfacing, sidewalks, driveways, garage floors, warehouse floors, and

for any other suitable purpose.

An object of this invention is to provide a process for producing asphalt coated shell consisting of washing, screening, heating and spraying so that it maybe completely prepared and '10 mixed at the factory and stored and handled in bulk prior to use.

A further object of this invention is to provide a method for producing an asphalt coated shell consisting of washing the mud shell obtained from a dead shell reef or the like, eliminating all foreign substances and reducing the shell particlesto a uniform size.

Hitherto, shell and asphalt surfacing has been made bylaying the shell on a base and applying the asphalt to it, and without washing the shell to remove the foreign and deteriorating sub stances; in such processes it isnecessary to obtain the mixing and combination at and during the construction, in order to avoid solidification.

. This invention provides a method for makinga material which may be entirely prepared and mixed at the factory and stored in bulk ready for use. process of washing, screening, heating and spraying.

screen where clean water at about 10 pounds pressure is sprayed on it.

The vibrating screen serves to keep the shell in constant motion by severely vibrating it, maintaining it loose and agitated so that the clean water comes in contact with every particle of shell, and at the same time grades it by causing all the material that is deteriorated and too fine for use to pass off with the washing water which L59. flows through the finest screen on the lower deck of the vibrator. V

The constant vibrating and agitating of the shells against each other is necessary to leave a rough surface on the shell particles to make them I; adhesive for the asphalt treatment.

This material being made by a special After the shell has passed over the vibrating screen, it is discharged into a special device known as a water conveyor which has clean running waterin it and serves to give the shell the final washing and also to convey it to the storage bin or pile. The shell is agitated several times after it is taken out of the storage pile and before it goes into the heat treatment. This agitation allows the air to come into contact with all of the shell; the action of the air oxidizes the shell causing a thin coating to form thereon.

The shell then passes through a specially designed heating and mixing apparatus having a centrifugal motion and at the same time is severely agitated. After the shell has reached a suitable temperature of about 200 degrees F. and a rough adhesive surface provided, the refined asphalt or bituminous material of about the same temperature is sprayed on the shell in sufficient quantity and with sufficient pressure to coat the shell thoroughly,v using from approximately 10 to 25 gallons of refined asphalt or bituminous material per ton of shell, depending on the purpose for which it is to be used or the richness desired. v

. After the shell has passed through the heating and mixing process it may be applied to the road surface or wherever it is to be used while hot, or, if it is so desired, the shell may be placed in a storage pile, or loaded in cars of a suitable type for transportation to the place where it is to be used. The process of oxidation and heating functions to make the refined asphalt or bituminous material hard and the sudden change in temperature serves to dry it. This leaves the shells with a dry coat of refined asphalt or bituminous material and the shell will not bind together or set until it has been spread in layers of the desired thickness onxthe surface for which it has been prepared and-sufliciently compressed be PATENT OFFICE traffic causes a hard smooth surface to form on top, making a seal adapted, to keep out all against each other for forming a rough adhesive surface thereon, spraying hot bituminous material on the shell until thoroughly coated and while both are heated to about 200 F., and then suddenly exposing the shell to cool air for drying and hardening the bituminous material, thereby producing coated shell.

r WILLIAM R. PARKER.

WILLIE L. HOLBROOK. 

